665757757566 has 192 divisors, whose sum is σ = 1663916567040. Its totient is φ = 190522080000.

The previous prime is 665757757549. The next prime is 665757757673.

It is a happy number.

665757757566 is a `hidden beast` number, since 6 + 6 + 5 + 7 + 5 + 7 + 7 + 57 + 566 = 666.

665757757566 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 665757757494 and 665757757503.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 48128271 + ... + 48142101.

It is an arithmetic number, because the mean of its divisors is an integer number (8666232120).

Almost surely, 2^665757757566 is an apocalyptic number.

665757757566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 665757757566, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (831958283520).

665757757566 is an abundant number, since it is smaller than the sum of its proper divisors (998158809474).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665757757566 is a wasteful number, since it uses less digits than its factorization.

665757757566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14063 (or 14060 counting only the distinct ones).

The product of its digits is 1944810000, while the sum is 72.

The spelling of 665757757566 in words is "six hundred sixty-five billion, seven hundred fifty-seven million, seven hundred fifty-seven thousand, five hundred sixty-six".